Sphagnum squarrosum | Spiky Bog-moss
|HABITATS DIRECTIVE ARTICLE 17 REPORTING*|
|Overall Assessment of Conservation Status||Inadequate|
|Overall Trend in Conservation Status||Stable|
The Conservation Status in the table above is then for the Sphagnum genus in Ireland rather than for the individual species.
Source: NPWS 2013; European Topic Centre on Biological Diversity.
|IUCN Conservation Status|
|Ireland (1)||Least Concern|
|Europe (2)||Not evaluated|
|Global (2)||Not evaluated|
Sources: (1) Lockhart, N., Hodgetts, N. & Holyoak, D. 2012; (2) The IUCN Red List of Threatened Species. Version 2014.3.
Protected by the following legal instruments:
- Habitats Directive [92/42/EEC] Annex V
All members of the Sphagnum genus are distinguished from other moss species by the combination of the following characteristics;
- The absence of rhizoids in the gametophyte, and the presence of groups of spreading and / or pendent branches (these groups referred to as fascicles) arranged at intervals along the main stem.
- As well as chlorophyllose cells (chlorocysts) Sphagnum leaves have adapted large dead cells, 'hyaline' cells, that allow Sphagnum species plants to retain water in relatively large amounts.
- The sporangium lacks the peristome seen in many other moss genera.
- Rather than the seta (stalk) seen in other mosses, in Sphagnum species the spore bearing capsule is borne on a pseudopodium.
- The top end of the plant, where new fascicles are formed, contain many young compact fascicles which give Sphagnum species a distintive 'mop-head' look. This terminal head is termed a capitulum.
- The lack of a leaf mid-rib or 'costa'.
Sphagnum squarrosum is one of two Irish Sphagnum species that are often referred to collectively as section Squarrosa. In the field these two species normally look quite different from each other.
- The terminal bud i.e. that in the centre of the capitulum is much more obvious than in most other Sphagnum species in that it is relatively large and conical.
- In S. squarrosum this terminal bud is slightly immersed in the capitulum, when viewed from the side. In S. teres which has a similar large, conical terminal bud it projects above the surrounding capitulum.
- May have between 2 and 4 spreading branches and between 2 and 4 pendent branches.
- The branch leaves, which are usually over 2mm long when fully developed, contract sharply in the middle from a fairly broad base, to form a quite pointed almost tubular leaf apex.
- Particularly in S. squarrosum this pointed branch leaf apex is recurved sharply away from the branch, which lends the plant an overall spiky 'appearance'.
- Stem leaves are large, parallel sided and overall tongue shaped and may be orientated in any direction, but often spreading from the stem.
- Colour is bright green.
- Well grown shoots to 20cm long.
- Well grown shoots to over 2.5cm wide, including fascicles.
- Capsules common.
- Confusion can be caused by S. palustre which, in shaded conditions, may also have recurved leaves but S. palustre has a wide outer cortex to inner pith ratio (outer cortex occupies about 1/3 or more of the diameter).
Sources: Atherton, I., Bosanquet, S., Lawley, M., 2010; Lockhart, N., Hodgetts, N. & Holyoak, D. 2012a; Smith, A.J.E. 2004;Hill, M.O., 1992.
Typical of moderately to well enriched swampy sites.
Habitats may include but are not necessarily limited to;
- Poor fen and flush (PF2)
- Transition mire and quaking bog (PF3)
- Wet pedunculate oak-ash woodland (WN4)
- Bog woodland (WN7)
- Highly modified / non-native woodland (WD)
- Drainage ditches (FW4)
- Eroding / upland rivers (FW2) Bank-side
Classic alternation of generations with diploid sporophyte and haploid gametophyte generations. In mosses the haploid gametophyte is the longer lived and obvious plant seen in the field.
The sporophyte is the capsule which is borne on a pseudopodium produced from tissue of the gametophyte.
Fertilization of female gametes by male gametes produces the diploid sporophyte. Meiosis of spore mother cells produce haploid spores, which are disseminated when the capsule opens. Spores germinate into a filamentous 'protonema' which will eventually produce the familiar moss gametophyte.Sources: Porley, R. Hodgetts N. 2005.
Sphagnum species can also spread vegetatively through the development of new stems from branches and may also spread via plant fragments.
In the Article 17 Habitats Directive reporting for the period 2007-2012 no threats were listed for this species. In that reporting period the named Sphagnum species of the Habitats Directive occurring in Ireland were given an 'Overall Assessment of Conservation Status' of 'Inadequate' due to;
- 'The poor conservation status of the peatland habitats within which the majority of Sphagnum species occur'.
In the Article 17 Habitats Directive reporting for the period
2007-2012 no Conservation Measures in place or in the process of being
implemented during the period were listed for this species.
This is a circumboreal species from arctic to temperate regions.
Hill, M.O. et al 1992
European records appear concentrated in Britain and Ireland, Norway, Sweden, Denmark and the Netherlands. Records also from Poland, Iceland, Germany, the Czech Republic, Austria, southern France, northern Spain, the south of Greenland, Svalbard.
Other records from central Asia and Japan. Records also from eastern North America and western North America,as well as New Zealand.
Accuracy of world distribution shown in the Global Biodiversity Information Facility (GBIF) map below will be constrained by, amongst other factors, data held but not shared by countries and organizations not participating in the GBIF.
Records are widepspread but not as frequent as in Britain. Currently there appears to be an eastern / northern distribution in Ireland.
Records submitted to Data Centre in 2023
The following map is interactive. If you would prefer to view it full screen then click here.
How can you help
The National Biodiversity Data Centre is trying to
improve our knowledge of the distribution of Sphagnum squarrosum in
Ireland. Should you observe this species, please submit
sightings to add to the database. Detailed observations will assist us
gaining a better insight into where the species
is most abundant in Ireland and we might also be able to detect
regional variations. Please submit any sightings and photographs at:
All records submitted online can be viewed on Google Maps – once checked and validated these will be added to the database and made available for conservation and research.
For further information contact Dr. Liam Lysaght firstname.lastname@example.org
Atherton, I., Bosanquet, S., Lawley, M., 2010. Mosses and Liverworts of Britain and Ireland a field guide. British Bryological Society.
Fossitt, J.A. 2001 A Guide to Habitats in Ireland. The Heritage Council.
Frey, W., Frahm, J.P., Fischer E., and Lobin W. 2006. The Liverworts, Mosses and Ferns of Europe. Harley Books, Colchester.
Hill, M.O., 1992. Sphagnum: A Field Guide, Revised by Hodgetts, N.G. & Payne, A.G., ISBN 1 87370 114 4
Hill, M.O., Preston C.D., and Smith A.J.E., 1992. Atlas of the Bryophytes of Britain and Ireland Vol. 2 Mosses (except Diplolepideae). Harley Books, Colchester.
Holyoak, D. T. (ed.). 2003. The distribution of bryophytes in Ireland: An annotated review of the occurrence of liverworts and mosses in the Irish vice-counties baseed mainly on the records of the British Bryological Society. Broadleaf Books, Wales.
Lockhart, N., Hodgetts, N. & Holyoak, D. 2012. Ireland Red List No.8: Bryophytes. National Parks and Wildlife Service, Department of Arts, Heritage and the Gaeltacht, Dublin, Ireland.
Lockhart, N., Hodgetts, N. & Holyoak, D. (2012a) Rare and Threatened Bryophytes of Ireland. National Museums of Northern Ireland.
Porley, R. and Hodgetts N. 2005 Mosses & Liverworts, Collins.
Rodwell, J.S. (ed.) 1991. British Plant Communities Vol.2 Mires and Heaths.Cambridge University Press.
Smith, A.J.E. 2004. The Moss Flora of Britain. Cambridge University Press.
The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 17 November 2014.